Modular building



FIG. 1 is a perspective view of a modular building showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a right side view thereof;

FIG. 5 is a left side view thereof; and

FIG. 6 is a top plan view thereof. 

The ornamental design for a modular building, as shown. 